Materno-foetal cell traffic by DNA finger printing and its biological Significance

我们以前曾报道，用T依赖抗原免疫怀孕小鼠，成功地诱导了子代对相关抗原的抗原特异性空斑形成细胞(PFC)反应的抑制。这种抑制不是由于注射的抗原、孕妇产生的抗体或哺乳期转移，而是依赖于完整的母体T细胞的存在。这是一种MHC受限的耐受方式，能够继续至少1/6的小鼠生命。在传统观点中，胎盘将扮演天然屏障的角色，不让细胞通过。然而，我们得到的结果强烈表明，母体T细胞通过胎盘，然后诱导耐受。在这个研究项目中，我们试图通过使用分子技术来证实母体细胞在胎儿循环中的存在。我们发现，在H-2复合体的II类EB基因中，一个高度多态的微卫星序列对于各种H-2等位基因的分子检测是非常有用的。为了追踪婴儿脾中的母体H-2等位基因，进行了DNA多态分析。主要程序包括从幼鼠基因组DNA中扩增和RFLP分析包含H-2特异性微卫星的DNA序列。结果表明，免疫孕鼠的母体T细胞通过胎盘进入胎儿体内，诱导子代产生抗原特异性免疫耐受。

We have previously reported that the immunization of pregnant mice with T-dependent antigens successfully induced suppression of the antigen-specific plaque forming cell (PFC) response to the relevant antigens in the offspring. This suppression was not due to the administered antigens, the antibodies produced by the pregnant mother, or lactational transfer, but was dependent on the presence of the intact maternal T cells. It was MHC-restricted manner tolerance and was able to continue at least 1/6 of the murine life. In traditional point of view, the placenta would act as a natural barrier and not allow the cells to pass through. However, the results we got strongly suggested that maternal T cells go through the placenta and then induce the tolerance. In this research project, we try to substantiate the presence of maternal cells in the fetal circulation through the use of molecular techniques. We have found that a highly polymorphic microsatellite sequence within the class II Eb gene of the H-2 complex is quite useful for the molecular detection of various H-2 alleles. For tracking maternal H-2, alleles in baby spleens, the method of DNA polymorphic analysis was carried out. The main procedure involved the PCR-amplification and RFLP analysis of the DNA sequence encompassing the H-2 specific microsatellite from the genomic DNA of baby mice. The results indicated that maternal T cells of immunized pregnant mice go through the placenta and into the fetal bodies, induce the antigen specific immunological tolerance in the offspring.